“…1 The single-equation framework has been adopted by Kusumastanto and Jolly (1997), Mickwitz (1995), Hanna (1992), Nowak (1992), Roy et al (1991), Houston et al (1989), Lin et al (1988), Bird (1986), DeVoretz (1982), Allan (1972), and Bell (1968). On the other hand, Asche (1996), Burton (1992), and Wellman (1992), Tsoa et al (1991), Ioannides and Whitmarsh (1987) have followed the system approach. The simultaneous equation approach has been followed by Angrist et al (1995), Roy et al (1992) and Bockstael (1977).…”